[Elecraft] K3 external qro keying line

[w8zn at comcast.net]

I've seen numerous posts about the PTT output line on the K3 and using older amps. Yaesu's, Kenwood's, Icom's all share the same issue. 



Unless you are running QSK and need instant keying, I would suggest adding a small 12v relay inside the K3 that the solid state device keys and presents the user with a set of dry, isolated contacts that can handle positive, negative and up to 250v DC or AC. I have added this to several K3's to protect the switching transistor from eventual destruction. Once again, if you are using QSK, solid state due to it's fast switching time is your only option. 



Yes, it means touching your K3 with a hot soldering iron, but it's a "pay me now or pay me later" thing, sooner or later it will blow the switch if you are hooking up older or HB amps that use other than low current positive keying voltages. 



Terry 


----- Original Message ----- 
From: "Greg - AB7R" <ab7r at cablespeed.com> 
To: elecraft at mailman.qth.net, 'Barry at mailman.qth.net, "Stephen'" <pbsbarry at buffalo.edu> 
Sent: Thursday, February 12, 2009 10:18:50 AM GMT -05:00 US/Canada Eastern 
Subject: Re: [Elecraft] K3 external qro keying line 

Barry, The key out line on the K3 on not on a sub assembly, it is on the main RF board. Im not sure of the relay on the SB220 but I suspect you may need to use one of those AmpKeyer interfaces that the HeathGuy or Ameritron sells just to be safe...or brew your own. It depends on the voltage requirement of the amp's relay. ------------------------- 73, Greg - AB7R Whidbey Island WA NA-065 On Thu Feb 12 7:13 , "Barry, Stephen" sent: > > > > > > > > > > > > > > > > > > >I���m a long time builder/operator of an early K2 (s/n >377) and have considered going for the K3/10. > >�� > >I would use my SB220 occasionally for more power since I can >get approx. 200 watts with 12 watts in. > >�� > >The question I have is there a PA key line available from >the basic K3? ��Or, is that circuitry on the KPA3 subassembly? > >If so, has anyone found a way to key an amp with the basic K3? > >�� > >I enjoy reading the list serve and the good advice from some >of the O/T submitters such as W2FPR, AC7AC and N0SS.�� Thanks > >guys. > >�� > >I���d ask the Elecraft guys but I don���t want to >bother them while they���re cranking out K3s. > >�� > >73. > >�� > >Steve/AE2G > >�� > >�� > > > > > > 
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